The compound enterobactin is a very effective sequestering agent for iron, forming an unusual macro-bridged hexacoordinate trianon. Enterobactin is capable of removing iron even from Transferrin. It is produced in small quantities by E. Coli and related enteric bacteria when grown on iron deficient media. Chemically, enterobactin comprises three serine molecules linked to a macrocyclic trilactone substituted by three catechol residues as ligating side chains. This compound has been prepared by total synthesis by Corey et Bhattacharyya, Tetr. Letters 3919 (1977). Another synthesis of enterobactin has been reported by Rastetter, J. Org. Chem 45, 5012 (1980). Both methods of synthesis are based on the stepwise condensation of serine derivatives to a linear trimer and the subsequent cyclization of same.